login
A122885
a(n+1) = 4*a(n) + 11*a(n-1) - 2*a(n-2).
4
1, 13, 61, 385, 2185, 12853, 74677, 435721, 2538625, 14798077, 86245741, 502684561, 2929845241, 17076419653, 99528607141, 580095354265, 3381043256305, 19706164707853, 114855943942237, 669429501042721
OFFSET
1,2
FORMULA
a(n+1) = 4*a(n) + 11*a(n-1) - 2*a(n-2).
G.f.: x*(1+9*x-2*x^2)/((2*x+1)*(1-6*x+x^2)). - R. J. Mathar, Aug 12 2009
MATHEMATICA
LinearRecurrence[{4, 11, -2}, {1, 13, 61}, 25] (* Paolo Xausa, Jul 19 2024 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
More terms from Paolo P. Lava, Jul 09 2008
STATUS
approved